Mercedes C 300 AMG Line Edition De Auto (2021)
Estimated running costs and MOT pass rates from 395 MOT tests in 2024.
Annual Cost
£1,852
£154/month
MOT Pass Rate
90%
Excellent
Road Tax
£200
Standard rate/year
Est. Insurance
Grp 18-32
1950cc Diesel hybrid
Great Choice
90% pass rate, £1,852/year to run. 8 points above average.
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Annual Running Costs
~48 mpg (diesel-engine estimate; hybrids usually use less)
Standard rate (from April 2017)
Low estimate due to excellent reliability
Estimates based on 7,400 miles/year (UK average), diesel at 199.33p a litre (GOV.UK weekly average, week of 19 October 2026), GOV.UK road tax rates and repair likelihood from MOT data. Insurance not included. Cars registered from April 2017 pay the £200 standard rate, plus £440 a year for five years (from the second year) if they cost over £40,000 new (over £50,000 for electric cars).
Reliability Verdict
Excellent reliability. Very few MOT failures. That's 8 points above the average of 82% across all models in our data.
90% of MOT tests on Mercedes C 300 AMG Line Edition De Autos from 2021 ended in a pass in 2024, when they were about 3 years old. That's based on 395 tests across the UK, retests included. The average mileage recorded at those tests was 49,476 miles.
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How Does It Compare?
Mileage Analysis
49,476
Average miles
22,200
Expected for age
The average 2021 Mercedes C 300 AMG Line Edition De Auto had 49,476 miles on the clock at its 2024 MOT, which is well above the expected 22,200 miles for a 3-year-old car. Check service history carefully, as high-mileage cars need consistent maintenance to stay reliable.
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Mercedes C 300 AMG Line Edition De Auto by Year
Similar Cars to Consider
Land Rover Discovery Sport R-DYN SE D A
2020 · 1999cc Diesel hybrid
£1,852/year
90%
same
BMW 520D M Sport MHEV Auto
2021 · 1995cc Diesel hybrid
£2,002/year
89%
-1%
BMW 320D M Sport MHEV Auto
2021 · 1995cc Diesel hybrid
£1,852/year
91%
+1%
Volvo XC90 R-Design B5 MHEV Awd Auto
2021 · 1969cc Diesel hybrid
£1,852/year
90%
same
Check a Specific Mercedes C 300 AMG Line Edition De Auto
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About the 2021 Mercedes C 300 AMG Line Edition De Auto
The 2021 Mercedes C 300 AMG Line Edition De Auto is a premium car. Our records list a 1950cc diesel hybrid engine, though engines vary between versions. 395 MOT tests were recorded on this model in 2024, making it a less common model in the UK market. It sits in the bottom 25% of 2021 models for MOT pass rate.
With an average of 49,476 miles recorded at its 2024 MOT tests, Mercedes C 300 AMG Line Edition De Auto owners cover more miles than the average driver. High-mileage examples should be checked carefully for wear on suspension, brakes, and drivetrain components.
2021 Mercedes C 300 AMG Line Edition De Auto Fuel Costs
The 1950cc diesel hybrid engine offers a reasonable balance between performance and economy. Our estimate uses around 48 mpg, the figure for a diesel engine of this size, which works out to roughly £1,397 per year with diesel at 199.33p per litre (GOV.UK weekly average, week of 19 October 2026; based on 7,400 miles per year). As a hybrid it should use less than that, and real-world fuel costs depend a lot on how much electric-only driving you do.
What does it cost to own a 2021 Mercedes C 300 AMG Line Edition De Auto?
Total estimated annual running cost is £1,852 (£154/month), broken down as £1,397 fuel, £200 road tax, £55 MOT, and £200 predicted repairs. The low repair estimate reflects the excellent 90% pass rate. These cars rarely fail their MOT, so unexpected bills are less likely.
Buying a Used 2021 Mercedes C 300 AMG Line Edition De Auto
At 5 years old, the Mercedes C 300 AMG Line Edition De Auto offers good value with plenty of life remaining. Most manufacturer warranties will have expired, so a pre-purchase inspection is worth the cost.
Common Issues to Watch For
These are typical issues for cars of this age, fuel type and engine size, not faults recorded on this model's MOT tests. Use them as a checklist when you view one.
Hybrid Battery Health
Medium riskAfter 5 years, hybrid battery capacity may have reduced. A full replacement costs £2,000-£4,000, though reconditioning is cheaper at £500-£1,500.
Inverter and Power Electronics
Low riskThe inverter converts DC to AC for the electric motor. Failures are expensive (£1,500+) but relatively rare. Listen for unusual buzzing sounds.
Regenerative Braking
Medium riskBrake discs can corrode from reduced use (the electric motor handles most braking). Surface rust is normal but deep pitting needs attention.
Service History
Low riskAlways request a full service history. Regular servicing is the single best indicator of how well a car has been maintained, regardless of mileage.
Running Costs Compared
How the 2021 Mercedes C 300 AMG Line Edition De Auto stacks up against similar cars for estimated annual running costs, insurance group, and tax.
| Car | Pass Rate | Fuel/yr | Tax/yr | Est. Ins. Group | Total/yr |
|---|---|---|---|---|---|
| Mercedes C 300 AMG Line Edition De Auto(2021) | 90% | £1,397 | £200 | Grp 18-32 | £1,852 |
| Land Rover Discovery Sport R-DYN SE D A(2020) | 90% | £1,397 | £200 | Grp 18-32 | £1,852same |
| BMW 520D M Sport MHEV Auto(2021) | 89% | £1,397 | £200 | Grp 18-32 | £2,002+£150 |
| BMW 320D M Sport MHEV Auto(2021) | 91% | £1,397 | £200 | Grp 18-32 | £1,852same |
| Volvo XC90 R-Design B5 MHEV Awd Auto(2021) | 90% | £1,397 | £200 | Grp 18-32 | £1,852same |
Estimates based on 7,400 miles/year, GOV.UK average pump prices for the week of 19 October 2026, GOV.UK road tax rates and MOT data. Insurance groups are our rough estimate from engine size, not official groups. Actual costs vary by driver, location, and usage.
Questions about the 2021 Mercedes C 300 AMG Line Edition De Auto
Is the 2021 Mercedes C 300 AMG Line Edition De Auto reliable?
Excellent reliability. Very few MOT failures. 90% of MOT tests on 2021 Mercedes C 300 AMG Line Edition De Autos ended in a pass, from 395 tests (DVSA MOT data for tests in 2024, retests included). That's 8 points above the average of 82% across all models in the same data.
How much does a 2021 Mercedes C 300 AMG Line Edition De Auto cost to run?
Our estimate is £1,852 a year (£154 a month): £1,397 fuel, £200 road tax, £55 MOT and £200 predicted repairs, based on 7,400 miles a year. Insurance is not included.
What is the MOT pass rate for a 2021 Mercedes C 300 AMG Line Edition De Auto?
90% of 395 MOT tests on the 2021 Mercedes C 300 AMG Line Edition De Auto ended in a pass (DVSA MOT data for tests in 2024, retests included). That ranks it 2503rd of 3,336 models first registered in 2021 (bottom 25%).
Which year Mercedes C 300 AMG Line Edition De Auto has the best MOT pass rate?
Of the years with at least 100 tests, the 2021 Mercedes C 300 AMG Line Edition De Auto has the highest MOT pass rate at 90% and the 2020 the lowest at 89%. Newer cars usually pass more often simply because they are younger and have done fewer miles.
What is the average mileage for a 2021 Mercedes C 300 AMG Line Edition De Auto?
The average mileage recorded at MOT tests on the 2021 Mercedes C 300 AMG Line Edition De Auto is 49,476 miles, which is well above the expected 22,200 miles for a 3-year-old car. Check service history carefully, as high-mileage cars need consistent maintenance to stay reliable.
Related Mercedes Models
Explore other Mercedes cars or similar models in the same category.
Mercedes A
2019 · 1461cc Diesel
Mercedes C
2017 · 1991cc Hybrid
Mercedes A-Class
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Land Rover Discovery Sport R-DYN SE D A
2020 · 1999cc Diesel hybrid
BMW 520D M Sport MHEV Auto
2021 · 1995cc Diesel hybrid
BMW 320D M Sport MHEV Auto
2021 · 1995cc Diesel hybrid
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